Roller-vane hydraulic machine

ABSTRACT

The roller-vane hydraulic machine comprises a hollow casing (1) having working fluid inlet and outlet passages (2, 3). The casing (1) is provided with hollows opening into the space of the casing (1), said hollows accommodating rollers (4) interacting with a rotor (5) located inside of the casing (1). The casing (1) is provided with vanes (6) which, together with the casing (1) form a working space (7) divided by the rollers (4) into larger and smaller inter-roller chambers (8, 9) intercommunicated in pairs by hydraulic relief passages (14, 15). The rollers (4) have slots for the passage of the vanes (6) of the rotor (5). The larger and smaller inter-roller chambers (8, 9) are intercommunicated in pairs by passages (14, 15, 16, 17) in the casing (1).

TECHNICAL FIELD

The invention relates to mechanisms serving as a motor or pump whereinthe working fluid is liquid or gas and more particularly, it relates toroller-vane hydraulic machines.

BACKGROUND OF THE INVENTION

Known in the prior art is a roller-vane hydraulic machine (SU, A,567844) comprising a hollow casing with working fluid inlet and outletpassages.

The casing accommodates a rotor with vanes and slotted rollers. Therotor and rollers rotate in synchronism under the effect of the suppliedenergy. The casing and rotor surfaces form a working chamber divided byrollers into larger and smaller inter-roller chambers. The surfaces ofthe rollers form sealing clearances together with the surfaces of thecasing and rotor. The smaller inter-roller chambers intercommunicatethrough hydraulic relief passages in the casing. The hydraulic relief ofthe rotor in the hydraulic machine is incomplete due to the followingreason. In the course of rotor rotation there comes a moment when thelarger inter-roller chambers get closed. Then the pressure difference inthese chambers may reach considerable values.

This brings about a unilateral pressing of the rotor against the casingand a change in the sealing clearances. This leads to increased internalleaks on the working stroke and increased pressure losses on the idlestroke.

The mechanical and volumetric efficiencies of the hydraulic machinedepend to a considerable measure upon the length of the rotor vanessince just this length determines the length of contact surface betweenthe rotor and casing in case of rotor pressing and the length of thesealing clearances through which the working fluid passes. As a result,the unilateral pressing of the rotor against the casing reduces therange of rotation frequencies (practically precluding operation at lowfrequencies) and decreases the service life and reliability of themachine.

Known in the art is another roller-vane hydraulic machine (SU, A,992821) comprising a hollow casing with working fluid inlet and outletpassages and with hollows which open into the casing space. The hollowsaccommodate rollers directly interacting with the rotor accommodatedinside the casing. The rotor is provided with vanes and, in combinationwith the casing, forms a working space divided by rollers into largerand smaller inter-roller chambers intercommunicated in pairs through thehydraulic relief radial passages made in the rotor. The rollers haveslots for the passage of the rotor vanes, said rotor being installedwith a provision for rotating in synchronism with the rollers under theeffect of the supplied energy. The surfaces of the rollers form sealingclearances with the surface of the rotor. At the moment when the rollerspass the holes in the radial hydraulic relief passages in the rotor, thesealing clearances formed by the surfaces of the rollers and rotorbecome radically larger. This brings about a sharp growth of workingfluid leaks which may result in stoppages of the rotor or, at the best,in its jerky motion. Operation at low speed in this case becomesimpossible due to leaks of the working fluid.

SUMMARY OF THE INVENTION

The main object of the invention resides in providing a roller-vanehydraulic machine wherein the redistribution of the hydraulic relief andselection of the optimum length of the rotor vanes would ensure a widerange of rotor rotation frequencies.

This object is attained by providing a roller-vane hydraulic machinecomprising a hollow casing with working fluid inlet and outlet passagesand hollows opening into the casing space, said hollows accommodatingrollers directly interacting with the rotor accommodated in the casing,having vanes and forming, in combination with the casing, a workingspace divided by rollers into the larger and smaller inter-rollerchambers intercommunicating in pairs through hydraulic relief passagesand the rollers have slots for the passage therethrough of the vanes ofthe rotor installed with a provision for rotating in synchronism withthe rollers under the action of the supplied energy wherein, accordingto the invention, the larger and smaller inter-roller chambersintercommunicate in pairs through hydraulic relief passages in thecasing, the geometric centres of holes of said passages being arrangeddiametrically opposite and lie in the plane normal to the longitudinalplane of symmetry of the casing on the section limited by the planespassing through the geometric centres of the adjacent vanes and throughthe rotation axis of the rotor.

It is predictable that the larger and smaller inter-roller chambers beintercommunicated in pairs by means of additional hydraulic reliefpassages located in the longitudinal plane of the rotor body andconnecting in pairs the grooves provided on the face surfaces of therotor.

It is also practicable that the length of the rotor vanes should beselected within a range of 0.8 to 3 roller diameters.

Connecting the larger and smaller inter-roller chambers in twos by thehydraulic relief passages made in the casing and by the additionalhydraulic relief passages located in the longitudinal plane of the rotorbody and connecting in twos the grooves on the face surfaces of therotor makes it possible to relieve completely the rotor in the axial andradial directions. The length of the rotor vanes varying from 0.8 to 3roller diameters ensures serviceability of the hydraulic machine atminimum leaks of the working fluid. This ensures a wider range of rotorrotation frequencies, increase in the efficiency of the hydraulicmachine, higher reliability and durability.

BRIEF DESCRIPTION OF THE DRAWINGS

Now the invention will be described by way of example with reference tothe accompanying drawings in which:

FIG. 1 is a schematic view of the roller-vane hydraulic machineaccording to the invention, cross section;

FIG. 2 is a section along line II--II in FIG. 1, longitudinal section;

FIG. 3 is a longitudinal sectional view taken along line III--III inFIG. 1.

FIG. 4 is a Section along line IV--IV in FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

The hydraulic machine is comprised of a hollow casing 1 (FIG. 1)provided with working fluid inlet and outlet passages 2, 3 and withhollows opening into the space of the casing 1. The hollows accommodaterollers 4 directly interacting with the rotor 5 located in the casing 1and provided with vanes 6. The working space 7 is formed by the internalsurface of the casing 1 and by the surface of the rotor 5. Said workingspace 7 is divided by rollers 4 into larger and smaller inter-rollerchambers 8, 9.

The surfaces of rollers 4 in combination with the surface of the casing1 form sealing clearances 10 while in combination with the surface ofthe rotor 5 they form sealing clearances 11. The surface of the casing 1in combination with the surface of the rotor 5 forms face sealingclearances 12 (FIG. 2) while in combination with the surface of vanes 6it forms sealing clearances 13 (FIG. 1).

The rotor 5 has six vanes 6 (most preferable layout). The angle α formedby the sections of straight lines passing through the geometricalcentres of the adjacent vanes 6 and through the rotation axis of therotor 5 is equal to 60°. However, other layouts of the hydraulic machineare also possible, for example with 4, 8, 10 etc. vanes for which thisangle is, respectively, 90°, 45°, 36°, etc.

The larger and smaller inter-roller chambers 8, 9 are intercommunicatedin twos by passages 14, 15 (FIG. 1), 16, 17 (FIG. 3) intended for radialhydraulic relief of the rotor 5. The hydraulic relief passages 14, 15(FIG. 1) are made in the casing 1 and intercommunicated in twos bypassages 16, 17 (FIG. 3).

The passages 16, 17 are made between the casing 1 and the outer races ofbearings 18. The holes of the passages 14, 15 (FIG. 1) are located onthe radius R₁ whose value varies from R₂ <R₁ <R₃ where R₂ =rollingradius of the rotor 5, R₃ =radius of the roller 4 over the vanes 6. Thehydraulic relief passages 14, 15 are connected in twos, arrangeddiametrically opposite and their axes lie in the plane passing throughthe rotation axis of the rotor 5. The diameter of holes in the passages14, 15 should not exceed the width of the vanes 6 on the R₁ radiusotherwise the pressures at the inlet and outlet of the machine maybecome combined. The passages 15 may be made in one or more pairs. Thepassages 16, 17 (FIG. 3) may be in other parts, such as, for example, inthe journals of the rotor 5. The geometrical centres of holes in thehydraulic relief passages 14, 15 (FIG. 1) lie in the plane normal to thelongitudinal symmetry plane of the casing 1. The geometrical centres ofthe passages 15 lie on the section limited by the planes passing throughthe geometrical centres of adjacent vanes 6 and the rotation axis of therotor 5.

The passages 14, 15, 16, 17 (FIG. 1, FIG. 3) are made so as to ensureradial relief of the rotor 5 in any position it occupies relative to thecasing 1 and rollers 4 by communicating the smaller inter-rollerchambers by passages 14 and further, through passages 16, andcommunicating the larger inter-roller chambers by passages 15 andfurther through passages 17.

The passages 15 may be arranged both on the symmetry axis of thehydraulic machine and in any interval of the angle α. The pairedpassages 15 are always located diametrically opposite and their axes liein the plane passing through the rotation axis of the rotor 5.

Additional hydraulic relief passages 19, 20 (FIG. 1) are arranged in thebody of rotor 5 and connect in pairs circular grooves 21, 22 (FIG. 1,FIG. 2) made on the end faces of the rotor 5. The grooves 21, 22 are ofthe intermittent design. The intermittent shape of grooves 21, 22improves the efficiency of hydraulic relief since it has a substantialeffect on restoring the plane-parallel configuration of the face sealingclearance 12 if it has previously been of the conical shape. The grooves21, 22 may also be continuous. However, the intermittent shape of thegrooves 21, 22 is preferable since the continuous groove will proveefficient only with the plane-parallel face sealing clearance 12 and isineffective if said clearance 12 has previously been conical. Thegrooves 21 of a larger area are located nearer to the axis of the rotor5. The grooves 22 of a smaller area are interconnected by the hydraulicrelief passages 19, 20 located in a longitudinal plane of the body ofthe rotor 5 with the grooves 21 of a larger area located on the oppositeface ends of the rotor 5. The number of grooves 21, 22 on each facesurface of the rotor 5 must be not less than one (in this case it shouldbe fully circular). It is practicable that the number of grooves 21 and22 should be not less than two or three on each face of the rotor 5. Thegrooves 21, 22 may be made on the face surfaces of the casing 1.However, the provision of the grooves 21, 22 on the face surfaces of therotor 5 is preferable for the following reason. If the grooves 21, 22are made on the face surfaces of the rotor 5, the passages 19, 20 duringits rotation are not overlapped by bridges 23 (FIG. 1) between theadjacent grooves 21 or 22 (FIG. 2) as would have happened if the grooves21, 22 were made on the face surfaces of the casing 1.

The provision of passages 19, 20 in the rotor 5 intercommunicating thegrooves 21, 22 ensures axial hydraulic relief of the rotor 5 of thehydraulic machine which excludes the endwise pressing of the rotor 5against the casing 1 and changes of the face sealing clearances 12 whosevalue determines to a considerable extent the leaks of the working fluidand, consequently, the range of rotation frequencies of the rotor 5.

The axial hydraulic relief of the rotor 5 contributes to increasing theefficiency, reliability and durability of the hydraulic machine. Therollers have slots 24 (FIG. 1) for the passage of the vanes of the rotor5 which is installed with a provision for synchronous rotation with therollers 4 under the action of the supplied energy. The length 1 of thevanes 6 of the rotor 5 (FIG. 2) is selected within 0.8 to 3 diameters ofthe roller 4.

This length of the vanes 6 of the rotor 5 ensures efficient service ofthe hydraulic machine with minimum leaks of the working fluid, therebybroadening the range of the rotor rotation frequencies and raising theefficiency of the machine. Selection of this length of the vanes 6 ofthe rotor 5 is explained by the following. If the length 1 of the vanes6 of the rotor 5 is larger than 3d where d=diameter of the roller 4, thetotal length of the recess (including the recess for the bearing 18)will be 1>5d which is difficult technologically. Besides, the length ofthe vanes 6 exceeding 3d results in larger face sealing clearances 12.This goes together with increased leaks of the working fluid and,consequently, with a reduction of the range of rotation frequencies andthe efficiency of the machine.

The length of the vanes 6 smaller than 0.8d is not recommended for thefollowing reason. The working volume V_(o) of the hydraulic machine canbe found from the expression ##EQU1## D₁ =diameter of the rotor 5 overits vanes 6; D₂ =rolling diameter of the rotor 5. The required workingvolume can be obtained either by increasing the length of the vanes 6 orby increasing the diameter of the rotor 5. The second method is lessacceptable since it results in an unwarranted development of the facesealing clearances 12 which, in turn, leads to heavier leakage of theworking fluid and, as a consequence, to a narrower range of rotationfrequencies and a lower efficiency of the machine.

The hydraulic machine according to the invention functions as follows.

The rotor 5 (FIG. 1) with the vanes 6 is rotated by the supplied energy,conveying the working fluid into the passage 3. Rotation of the rotor 5is accompanied by rotation of the rollers 4 in synchronism with therotor. The hydraulic machine has an even number of rollers 4, two largerinter-roller chambers 8 and two smaller inter-roller chambers 9,arranged diametrically opposite to the rotation axis of the rotor 5. Inthe course of rotation, one group of rollers 4 lets pass the vanes 6while the remaining rollers 4 in combination with the surface of thecasing 1 form a sealing clearance 10 and, in combination with the rotorsurface, a sealing clearance 11. The surface of the casing 1 incombination with the surfaces of the vanes 6 forms sealing clearances13. The sealing clearances 10, 11, 12, 13 (FIG. 1, FIG. 2) dividepressure at the inlet 2 and outlet 3 (FIG. 1). Simultaneously, the rotor5 is axially and radially relieved. The radial relief of the rotor 5 iscarried out by connecting in pairs the larger and smaller inter-rollerchambers 8, 9 by hydraulic relief passages 14, 15 (FIG. 1, FIG. 3 andFIG. 4) and 16, 17 made in the casing 1.

Axial relief of the rotor 5 (FIG. 1) is carried out by way of connectingthe larger and smaller inter-roller chambers 8, 9 through hydraulicrelief passages 19, 20 (FIG. 2) which connect the grooves 21, 22(FIG. 1) on the end faces of the rotor 5.

Investigations of four typesizes of hydraulic machines with workingvolumes V_(o) =40, 125, 1800 and 2000 cm³ /vol have revealed that saidhydraulic machines rendered steady service both in the motoring andpumping modes at the rotation frequencies of the rotor 5 ranging from0.1 to 3000 rpm including servo operation on oils with a viscosity rangeof 1-2000 mm² /s. Featuring a high efficiency within a wide range ofrotation frequencies and working pressures, these hydraulic machinesdevelop considerable torques at a small size and specific mass per unitof the working volume V_(o). These machines ensure a constant torque onthe rotor shaft in any position of the rotor and either direction of itsrotation.

The machines combine such hard-to-combine features as high torque andspeed.

INDUSTRIAL APPLICABILITY

The present invention will prove most effective in servo systems withina broad range of rotation frequencies. It can also be used in airmotors, compressors and internal combustion engines.

We claim:
 1. A roller-vane hydraulic machine having pressure balancing,comprising: a casing with working fluid inlet and outlet passages, aspace and an interior surface; at least two hollows opening into thespace of the casing; a rotor arranged in the space of the casing, therotor having vanes and an axis of rotation, said vanes defining aworking volume between the rotor and the casing; a roller disposed ineach hollow of the casing, the roller directly interacting with therotor, each roller having at least one slot for passing the vanes of therotor, when the rotor is rotated in unison with the rollers; first andsecond hydraulic relief passages with openings provided in the casing,geometric centers of the openings being diametrically opposite anddisposed in a plane perpendicular to a longitudinally extending axis ofsymmetry of the casing and passing through the geometric axis ofrotation of the rotor; large and small inter-roller chambers formed inthe working volume by the rollers wherein the small roller chambers arein fluid communication first by the hydraulic relief passages and thelarge roller chambers are in fluid communication by the second hydraulicrelief passages.
 2. A roller-vane hydraulic machine of claim 1,comprising: A first circular groove and a second circular groovedisposed coaxially on each end face of the rotor, the first groove beingarranged nearer the geometric axis of the rotor and having a greaterarea than the second groove being arranged further from the geometricaxis of the rotor; at least two third hydraulic relief passages arrangedin the rotor, each of the third hydraulic relief passages in the rotorconnecting the first groove on one end face of the rotor with the secondgroove on the other end face of the rotor.
 3. A roller vane hydraulicmachine of claim 2 wherein the length of the vane is equal to 0.8 to 3diameters of the rollers.
 4. A roller vane hydraulic machine of claim 1wherein the length of the vanes is equal to from 0.8 to 3 diameters ofthe rollers.